Use the given information to find the exact function value.

Question

Use the given information to find the exact function value. Simplify your answer as much as possible. Rationalize the denominator if necessary.

sinθ=4/7, tanθ>0

sin2θ=

cos2θ=

tan2θ=

Answer 1

You need frst to know what the other trig functions in this problem:

cos = sqrt(33)/7 and tan = sqrt(33)/4. (use the theorem of Pythagoras!)

The you need to use the double angle formulae...and if you don't by now have them in your head, you should simply look them up and plug in the values above. Be careful: the tan>0 which may be in quadrant 3!